Low pressure automatic change-over device



May 4, 1943. T. A. ST. CLAIR 2,318,261

I LOW PRESSURE AUTOMATIC CHANGEOVER DEVICE Filed Oct. 17, 1941 2 Sheets-Sheet 1 I6 I vi gm A y) a f/ 1,

INVENTOR T. A. ST CLAIR BY ,5 a l K 5 5 ATTOREEY Z 5 y 1943- T. A. ST. CLAIR 2,318261 LOW PRESSURE AUTOMATIC CHANGEOVER DEVICE Filed OCT 17, 1941 i 2 Sheets-Sheet 2 FIG. 2

INVENTOR 'T. A. ST CLAIR Patented May 4, 1943 2,318,261 LOW PRESSURE AUTOMATIC CHANGE-OVER DEVICE Theodore A. St. Clair, Pontiac, Mich., assignor to Phillips Petroleum Company, a corporation of Delaware Application October 17, 1941, Serial No. 415,459

4 Claims.

The present invention relates to a fully automatic changeover device for the transfer of with- -drawalconnections from one source of high pressure gas to another upon decrease in pressure in the first source.

Liquefied petroleum gases such as, propane, butane, or mixtures of the two have revolutionized domestic operations such as heating and cooking in rural communities and a great industry has arisen which is engaged in producing the fuel and the manufacture of equipment suitable for its handling by domestic consumers. aim of manufacturers has been the development of a self-service system which can be safely manipulated by persons entirely unskilled in mechanical contrivances with the greatest of ease and which requires a minimum of care and attention. It is customary to provide the customer with two containers with some means of connecting them to a service line to the gas consuming appliance through a suitable ararngement of valves and pressure regulators. One of the cylinders is ordinarily used as the active source of gas supply. while the other serves as a reserve source until the first cylinder is exhausted, usually evidenced by some sort of indicating means. It has been desirable to effect the connection of the re- The primary cation when a change of withdrawal connections has taken place.

Figure 1 shows diagrammatically a sectional view of one form of my improved changeover valve.

Figure 2 illustrates the use of my improved changeover valve in a self-service system for disserve cylinder with the service line automatically to avoid a temporary cessation of supply of the gaseous fuel. Various automatic and semi-automatic arrangements have been previously proposed to accomplish change of withdrawal connections, one of which utilized a valve in each conduit acting againstthe flow of gas under unequal spring pressure set by a manually operable device which it was necessary to reset every time the exhausted cylinder was replaced with a full one. A number of other fully automatic changeover valves have been suggested, but none have enjoyed extensive use due to their complicated construction which not only was prohibitive from a manufacturing standpoint, but added to the operating costs due to necessary periodic adjustment and replacement of parts. The changeover valve which I have developed is characterized by simplicity of construction and ease of manipulation, which I believe overcomes the objection inherent in prior structures.

A primary object of the present invention is to provide an improved changeover device which is iul y autrmatic and of simplified construction while be ng entirely eflicient and positive in its cperatlon;

A further object is the development of an au-. tomatic changeover device which iscomposed of a minimum number of parts and depends for its operation on decrease in pressure from a supply source.

Another object of this invention is to provide a changeover device for liquefied petroleum gas dispensing systems which will give a visual indipensing liquefied petroleum gases.

Referring to Figure 1, the numeral I designates generally the changeover valve, the casing l' of which is comprised of three parts, namely, end members 2 and 3 and intermediate member 4, which are suitably secured together by bolts or the like in the relationship shown in the draw-- ing. The end members 2 and 3 are provided with left and right hand inlets 5 and 6, respectively, which connect with cylindrical containers of liquefied petroleum gasthrough suitable pressure regulators. The end members 2 and 3 are likewise provided with central flanges l and 8 for the formation of elongated cylindrical bores 9 and ID, as shown in the drawing. A valve actuating member or operating sleeve II is longitudinally moveable with respect to the cylindrical bores formed in the end members, and diaphragms l2 and i3 composed of synthetic rubher or other hydrocarbon resistant material are securely clamped between the end members 2 and 3 and intermediate member 4 of the casing. Although diaphragms have been shown in the specific embodiment illustrated, any suitable gas pressure responsive means may be utilized for shiftingthe valve actuating member. Pressure chambers I2A and I3A are thereby formed between the diaphragms and the end members 2 and 3, and a service chamber 4A is likewise formed between the diaphragms. The diaphragms I are provided with back-up plates 14 and IS. The operating sleeve has threaded sections I6 and I1 and a central enlarged section l8. The diaphragms l2 and J3 together with the back-up plates are rigidly secured to the operating sleeve between the enlarged central portion l8 and tubular clamping nuts l9 and 20. Cylinvalve seats 23 and 24, respectively. The diaphragms l2 and I3, rigidly secured to the operating sleeve, alternately act as valves when the sleeve is moved to the extreme left or right, engaging the respective valve seat and sealing oil the flow of gas through the passages formed between the cylindrical bores and the sleeve. A

central passage 25 is provided within the ope: ating sleeve which communicates with the pressure chambers HA and "A when the operating sleeve is in the extreme right or left hand position, respectively, and a passage 26 connects the central passage with the service chamber 4A. Supporting arm 2? extends to a point midway of the central chamber between the diaphragm from the side of the casing. One end of a spring snap lever 28 is pivoted on the end of the-arm at 29. while the opposite end is nested in a socket 30 situate'd'on the top of the operating sleeve, One end of a changeover spring 3| isconnected to an ear 32 on the inside of the intermediate casing section and the oppositeend of the spring is connected under tension near the lower end of the snap lever at 33.- The cylindrical shoulders 2| and 22 are slightly longer axially thanthe throw of the snap lever longitudinally of the sleeve, so that, for instance, when gas enters the pressure chamber I2A, unseating the diaphragm from the valve seat 23, the snap lever will move slightly past dead center before the shoulder 2i clears the end of the valve seat. An outlet 34 for the service chamber is provided in the lower portion of the intermediate section in the casing. The cylindrical bores are threaded near their outer ends for the attachment of covers 35 and 36 of glass, plastic or. other transparent material. The ends of the operating sleeve H are preferably colored red so that it is readily apparent when a change over has occurred and the exhausted cylinder is to be replaced by a full one.

Figure 2 shows the automatic changeover in a liquefied petroleum gas dispensing system. The storage cylinders 31 and 38 are provided with first stage regulators 39 and 40 which connect with the changeover inlets and 6 through gas withdrawal conduits comprising flexible tubes 4| and 42. If desired, a second stage regulator is secured in the service line 43. Where a second stage regulator is employed, the changeover operates under a relatively higher pressure. Howcontinue to occur from the right hand cylinder until the pressure in chamber l3A decreases due to the exhaustion of 'the cylinder and changeover will thereupon take place due to the pressure differential in the chambers I2A and I3A which forces the diaphragm l2 to the right until the snap lever 28 passes dead center, closing dia-.

' phragm 13 against valve seat 24.

ever, if the reduction to line pressure is accomplished by the first stage regulator, the changeover will operate under a low pressure and slight- 1y larger diaphragms should be employed,

The operation of my improved automatic changeover in a system for dispensing liquefied petroleum gas may be described as follows: When the left hand regulator is connected first to a cylinder, gas will enter the changeover inlet 5, pressuring the chamber HA and, due to the low pressure in chambers 4A and BA, move operating sleeve II to the right against the action of the changeover spring 3| until the snap lever 28 just passes dead center. At this time, a snap action will occur, due to the changeover spring. forcing the operating sleeve completely to the right and seating the diaphragm l3 on the valve seat 24. When the right-hand regulator is connected to the inlet 6, due to the fact that the regulators have approximately equal seatings, gas will enter the pressure chamber I3A at the same pressure as that existent in the chamber I2A. It is obvious that the pressure on the diaphragms l2 and I3 will be approximately equal, but due to the action of the changeover spring 3|, the diaphragm I3 will remain firmly seated against the valve seat 24. With the parts in the position shown in the drawing and when both regulators are connected into the changeover, gas flow will take place through the inlet 6, pressure chamber I3A, cylindrical bore l0, central passage 25 in the operating sleeve, passage 26 through service chamber 4A and to the second stage regulator or directly to the line through outlet 34. Flow will ufacturing costs, in addition to ease of manipulation and eiiiciency of operation.

I claim:

1. A system for dispensing liquefied gascomprising two containers for the gas and a valve housing, a service line for connecting the housing with gas consuming appliances, a gas withdrawal conduit connecting each container with the valve housing, a valvecontrolling each withdrawal conduit, a valve actuating member con- I meeting said valves, gas pressure responsive means connected with the valve actuating member and exposed to the gas pressure on the inlet side of the said valves.

2. A system for dispensing liquefied gas comprising two containers for the gas and a valve housing, a service line for connecting the valve housing with gas consuming appliances, a gas withdrawal conduit connecting each container with the valve housing, a valve controlling each withdrawal conduit, a valve actuating member connecting said valves movable between two positions to open one valve and close the other, gas

pressure responsive means associated with the valve actuating member and exposed to the gas pressure on the inlet side of said valves and means urging said valve actuating member into one or the other of said positions.

3. A system for dispensing liquefied gas comprising two containers for the gas and a valve housing, a service line for connecting the valve housing with gas consuming appliances, a gas withdrawal conduit connecting each container with the valve housing, a valve controlling each withdrawal conduit, a valve actuating member connecting said valves movable between two positions to open one valve and close the other and gas pressure operated means connected with the valve actuating member and responsive to pressure difierential on the inlet side of the valves to reverse their position.

4. A system for dispensing liquefied gas comprising two containers for the gas and a valve housing, a service line for connecting the valve housing with gas consuming appliances, 9. gas withdrawal conduit connecting each container with the valve housing, a valve controlling each withdrawal conduit, a valve actuating member connecting said valves movable between two positions to open one valve and close the other, loading means urging said valve actuating member into one or the other of said positions, and pressure responsive means connected with the valve actuating member and exposed to gas pressure on the inlet side of said valves adapted to overcome said loading. means and reverse the position of the valves on failure of pressure in one of said withdrawal conduits.

THEODORE A. ST. CLAIR. 

